Manufacture of lubricating oil



May 29, 1934. G. EGLoFF MANUFACTURE 0F LUBRICATING OIL Filed Deo. 18,1931 dim. but@ lill www Zjlozf www .SN bkmwkw Patented May 29, 1934MANUFACTURE F LUBRICATING OIL Gustav Egloff, Chicago, Ill., assignor toUniversal Oil Products Company, Chicago, Ill., a corporation of SouthDakota `Application December 18, 1931, Serial No. 581,835

2 Claims.

This invention relates to the manufacture of lubricating oils, andrefers more particularly to ythe manufacture of lubricants from crackingoperations on petroleum oils.

More specifically, lthe invention has reference to a process ofsynthesizing viscous fractions suit-V able foruse as lubricants from aportion or all y of the viscous products resulting from hydro- .carbonconversion reactions at elevated temperatures and pressures, a novelmethod and means for accomplishing this object being disclosedhereinafter.

In the conversion reactions attendant upon the pyrolysis of hydrocarbonsthere is a widening of boiling point range, free hydrogen beingliberated on the one hand, and a certain amount of coke or heavy pitchbeing produced on the other. Intermediate between these two end productsa -series of hydrocarbon fractions of regularly varying boiling pointoccurs containing varying amounts of hydrocarbons of the four generalseries, to-wit: parafiins, olelns,l naphthenes and aromatics in varyingproportions, with minor amounts of sulphur, nitrogen and oxygenderivatives, depending on the nature of the original stock cracked andthe conditions to which it was subjected.

It is usual in the operation of cracking heavy oils to produce motorfuel to regulate conditions to prevent or minimize the formation 'ofhighly unsaturated hydrocarbons of the olefin series since thesecompounds have objectionable features from thel standpoint ofinstability, their 35 tendency to polymerize resulting in thedevelopment of gu'mmy or resinous material on storage which isobjectionable in itself and which is accompanied by an intensificationof color which is objectionable from a sales standpoint in coni- 40mercial gasoline. Treatment of cracked distillates has, therefore, beengenerally directed toward the selective removal of the more highlyunsaturated oleilns which are thus necessarily produced in crackingprocesses. When such compounds are treated out by sulphuric acid andprises treating the vapors flashed from cracking residue with aluminumchloride.

In one particular type of commercial cracking operation, conditions oftemperature, pressure and time are regulated so that the conversion B0reactions are stopped short of the formation of any substantial amount`of solid carbonaceous residue. The liquid residuals may be removed fromthe process and utilized as fuel or a base for asphalt manufacture, orthey may be further 65 treated at slightly higher temperatures orpressures lower than the pressure in the heating and reaction zones todrive ofi a further quantity of light hydrocarbon vapors. It is commonlycharacteristic of the vapors thus flashed from cracked residua that theyare of a highly unsaturated character, probably owing to the lowhydrogen-carbon ratio in the cracked residua. The vapors thus producedprovide readily polymerizable material and it is with their conversionby polymerization with aluminum chloride that the present invention isconcerned. One of the most desirable properties of hydrocarbon oillubricants is a low temperature coefiicient of viscosity which isusually measured by the charge in its Saybolt viscosity when heated from100 to 210 F. compared with an adopted standard based upon thecorresponding change in a high class lubricant of proven value. Theexperimental and analytical data at hand show conclusively that thelower temperature coefflcients of viscosity are possessed by oils of the'highest straight chain or paraffin content, and that the highestcoefficients are characteristic of naphthenic oils. The property ofretaining viscosity or body at elevated temperatures is, therefore,predictable on a basis of the chemical constitution of hydrocarbon oilmixtures.

In the manufacture of synthetic lubricants by the liquid-phasepolymerization of individual 95 olefin hydrocarbons, it has been shownthat the best lubricants are, in general, produced from mono-olens ofrelatively high molecular weight, at least up to olens having 16 carbonatoms. It has also been shown that the polymerization of olenscontaining ternary and quaternary carbon atoms yields lubricants with ahigher viscosity temperature coefficient than those produced fromstraight chain oleilns of equivalent molecular Weight. Thus the resultsobtainable by the use of aluminum chloride to produce polymerizedlubricants from cracked flashed vapors will produce lubricants ofvarying value, depending upon the type of operation and charging stockused in the cracking process, land it 1.10

cants will be made by this process in plants em:- ploying highlyparafinic charging stocks such as are characteristic of Pennsylvania oilproducing areas.

The properties of aluminum chloride permit its use as a polymerizingreagent in a very simple manner since it is readily volatile withoutde-v composition at temperatures in the neighborhood of 360 F. underatmospheric or slightly superatmospheric pressures. The anhydrousmaterial can, therefore, be generated under slight pressure by heating abulk supply and the vapors injected into the vapor line or dephlegmatorof the flashing or evaporating elements of a cracking system to initiatethe desired polymerizing reactions. 'Ihe reactions may be substantiallycompleted in the vapor-phase and the reaction by-products consisting ofsludge-like or cokey aluminum chloride complexes may be either settledor filtered prior to condensation of the vapors, or in case theformation of sludge by-products is of a low order, the total vapors maybe condensed and the liquid products subjected to elevated temperatureswith agitation to insure the further action of the aluminum chloride inpromoting the vformation of viscous compounds.

After the reactions are substantially completed the sludge may beWithdrawn and the supernatant polymerized oil neutralized with alkalies,washed with water and redistilled with steam or under vacuum, ifnecessary, to produce lubricants of commercial grades with regard toviscosity range and other desirable properties. When flashed vaporscontaining relatively high percentages of saturated or non-polymerizablecomm pounds have been subjected to treatment, it may be found necessaryto subject the washed product i to preliminary reducing distillation toremove components of low viscosity.

By treating the aluminum chloride sludge with water or steam, it may bemade to undergo hydrolysis with the liberation of additional amounts ofoil. This oil may be utilized as fuel, blended with the raw oilchargingstock to the cracking -plant or fractionally distilled, in some cases,to produce vincreased yields of lubricating oil fractions, usually,however, of somewhat inferior grade to those produced as the principalproduct of the operation.

An example of one set of results obtainable by the use of the processwill serve to establish its value as a commercial improvement in themanufacture of -lubricating oils.-

A cracking plant may be operated upon a 26 A. P. I. gravity chargingstock consisting of 50% of topped Mid-Continent crude and 50% heavy 'gasoil distillate from the same general type of crude oils. The plantlayout in which the cracking is conducted may be of the type having alow pressure flashing chamberto recover additional quantities ofgasoline from the reaction chamber residuum upon reduction of pressure.Under ordinary operating conditions, the following approximate yields ofproducts .may be produced:

Loss, gas and coke 6 will be evident that the better grades of lubri- Ofthe total gasoline yield indicated, 5% may come from the flashing of thecracked residuum, this gasoline being of al highly unsaturated nature,for the reasons enumerated previously, and containing in fact 60 to 80%of unsaturated hydrocarbons. By injecting 4% ofaluminum chloride intothese flashed vapors at a temperature ofapproximately 400 F., they maybe caused to yield 60% of heavy viscous polymers, based on the vaporsundergoing treatment, utilizable as a base for lubricating oilmanufacture. The treated vapors after condensation may be reduced toproduce as 5% of the raw oil charged to the process a lubricating stockhaving a viscosity Saybolt of800 seconds at 100 F. and 85 seconds at 210F., this corresponding to a. viscosity n` dex of 110, indicating thatthe stock is approximately 10% better than the standard parafliniclubricant having a low coeilicient of viscosity change with temperature.

The overhead distillate obtained in the reduction of the polymerizeddistillate will be of -a saturated character and serve either for-directadmixture with the gasoline from the plant or as recycled stock forfurther conversiom The foregoing example will serve to indicate theeconomic value of the process when applied to flashed vapors from aparticular type of charging oil. However, since it maybe applied. whenother oils are subjected to the same type of cracking operation and isalso applicable'to the treatment of cracked vapors produced when theproducts are totally discharged from the reaction chamber, neither theforegoing example nor the details of the preceding disclosure are to bestrictly construed as imposing limitations the scope of the invention.

The accompanying drawing is a flow sheet diagrammatically illustrating apreferred embodiment ofthe process and is selfuexplanatory.

I claim:

1. In the 4cracking of heavy hydrocarbon oil wherein ythe cracked oil isseparated into vapors and unvaporized oil under pressure andtheseparated unvaporized oil flash distilled, the method which comprisesseparating the flashed vapors from the flashed residue and contactingthe same with aluminum chloride under conditions con-` ducive to theformation of lubricating oil fractions, condensing the thus treatedflashed vapors and separating'the lubricating oil fractions from theresultant condensate.

2. In the cracking of heavy hydrocarbon oil wherein the cracked oil isseparated into vapors and unvaporized oil under pressure and theseparated unvaporized oil flash distilled, the method which comprisesseparating the flashed vapors from the flashed' residue and contactingthe same with aluminum chloride vapors under conditions conducive to theformation of lubricating oil fractions, condensing the thus treatedflashed vapors and separating the lubricating oil fractions from theresultant condensate.

. lGUSTAV EGLOFF.

